import React, { Component } from 'react'
import './index.css'

export default class Footer extends Component {

    //全选checkbox的回调
    handleCheckAll=(event)=>{
        this.props.checkAllTodo(event.target.checked)
    }

    //清除已完成任务的回调
    handleClearAllDone=()=>{
        this.props.clearDoneTodo()
    }

    render() {
        const {todos}=this.props
        //已完成的个数
        const doneCount=todos.reduce((pre,todo)=>{return pre+(todo.done?1:0)},0)
        //总数
        const total=todos.length
        return (
            <div className="todo-footer">
                <label>
                <input type="checkbox" onChange={this.handleCheckAll} checked={doneCount===total&&total!==0?true:false}/>
                </label>
                <span>
                <span>已完成{doneCount}</span> / 全部{total}
                </span>
                <button onClick={this.handleClearAllDone} className="btn btn-danger">清除已完成任务</button>
            </div>
        )
    }
}
